[jcranmer]

What "petrodollar" refers to is the fact that oil producing countries (e.g., Saudi Arabia) have a vast surplus of oil revenue far in excess of their cost of production or ability to do anything internally useful with it. This means they have an extra stash of dollars that they need to do something with--and that stash of dollars is the petrodollar. It is a real phenomenon.

The problem is... it just doesn't have much relevance to geopolitics. The people who try to link it to such imagine that the US has a major foreign policy plank in upholding the use of dollars to price oil, to the point of starting wars purely to do so, despite such proponents not being able to offer a shred of evidence that any US official cared about this, or even being able to articulate what the supposed benefits the US receives from such pricing is.